Posts Tagged ‘Hohokam’

Name that Tune

Thursday, February 9th, 2012

  I moved to Phoenix about thirteen years ago, and as I drove around a bit back then and started learning my way around town, I took note of the various landforms surrounding us. I couldn’t quite put my finger on why, but South Mountain looked distinct to me — different from and more rounded than the other mountains that stick out of the relentless grid of asphalt and concrete that stretches on and on through the Valley of the Sun.

  I started looking into the reason, and one of the things I soon found out is that the rugged barrier at the south end of Central Avenue is correctly called the South Mountains (note the “s”). Where all the TV towers stand, and what most people refer to as “South Mountain”, is more properly named the Main Ridge. Looking south from the downtown area of Phoenix, you can also see a separate, smaller high point on the west end (right) of that rise. Its correct name is the Alta Ridge. Much lower, in front of it, and just next to the small town of Laveen, is the North Ridge.

  Speaking of names, the Pima Indian (Akimel O’odham) name for this set of peaks is “Muhadag Du’ag”, or “Greasy Mountain” — a take-off on the dark sheen of the rocks there, caused by a surface coloration known as “desert varnish”. If we really wanted to honor Native Americans, especially those who actually lived in the Valley, we would return its name to what they called it. We could have applied this line of thinking to certain other mountains around Phoenix as well, but I’ll save that discussion for another time.

  More often than not, like everyone else in town, I also call this aggregate of lumps South Mountain. The big point here is the way it looks -a long, low dome-shaped rampart. There is one simple reason for that: the rocks of South Mountain were pushed up, basically through the crust of the Earth. Most of the other ranges around us traverse central Arizona for the opposite reason: the landscape is being pulled apart on a massive scale. They are left standing as evidence of that strain as the valleys between them, like our own, drop away slowly, surely over time. Gravity never sleeps.

  South Mountain is what is called in geology-speak a Metamorphic Core Complex, and I’ll spare you some of the technical details. That term, which from now on in this article I’ll refer to as “MCC”, is a great name to throw around at cocktail parties, and one to remember if you are ever to be on one of those TV “Question & Answer” shows with big prize money. There is a whole, albeit small, subset of humanity out there that seems to be fascinated by them, and they’re not just geologists.

  Don’t ask me why, but one time, on a whim, I typed the term into a music-sharing website, and was amazed that a song actually came up with that name. Somebody (artist unknown) had in fact named a song to honor one! I downloaded it immediately, of course, certain the musician would not have minded. It is a spacey-sounding instrumental (naturally, and gladly) — I am not sure what kind of lyrics you could put to the subject of plate tectonics.

  There is “belt” of MCC’s across western North America, running from British Columbia down into Mexico. They run right through central Arizona, and South Mountain is one of the best of them. They are thought to represent an early phase of the “pulling apart” of North America. Around 25 million years ago, the crust started to stretch in a northeast to southwest direction. As it did so, it thinned out, and lighter rocks, which were once more deeply situated, basically “bobbed up” (the pushing-up I mentioned above) as sort of dome-shaped wrinkles — the South Mountains are one such dome.

  Then, millions of years later, the crust actually started to fracture and break apart. As you might expect, the resulting cracks — called faults — run perpendicular to the orientation of the stretching. This force, then, gave us the big valleys we inhabit, and left in-between massive blocks of rock standing — these are the mountains (Camelback Mountain and Squaw / Piestewa Peak, for example) around that have weathered into jagged summits with a character unlike that of South Mountain.

  I am continually perplexed by the number of Phoenicians who have told me they’ve never been up onto the South Mountains! There is no better view of the Valley than what you can get from Dobbins Lookout (the most popular spot). When you go that viewpoint, look just to the east, at the canyon wall just below you. There you will see the rocks all stretched out, horizontally, with very gentle curves from side to side — visible testimony of the doming forces that created the South Mountains MCC (see photo). Once you see that evidence, you will notice the same rock fabric everywhere around in those peaks.

  For more on MCC’s, look at a string of six photos beginning with a view of Central Phoenix from South Mountain. The fifth view in the sequence is a view from the Space Shuttle Atlantis, looking directly down onto the subject of someone’s favorite song.

Pathfinder

Sunday, January 8th, 2012

Ancient petroglyphs decorate a basalt boulder at the Deer Valley Rock Art Center in Phoenix, Arizona.

  Take take a look at the boulder in the picture above. You will notice that it is literally covered with markings and drawings. We call these “petroglyphs”, and they were created by pecking through the layer of desert varnish that coats many rocks in arid climates (as opposed to “pictographs”, which are painted onto rocks). Research has shown that petroglyphs in central Arizona were created between about 10,000 and 700 years ago, by peoples we now refer to as Paleo-Indian, Archaic, and Hohokam.

  But, as those of you who read my GeoStories know by now, there is more than that about them that would interest me. What really arouses my curiosity is why they are there.

  They are found in various places around the Valley of the Sun. But why in one place and not another? There are plenty of rock faces and walls scattered around our area. Some have no markings, and others, like the boulders at the Deer Valley Rock Art Center, just off I-17, north of Phoenix, have hundreds or more. Operated by Arizona State University’s Department of Anthropology, this place alone preserves over 1500 such works of art.

  Here, a trail approximately .25 mile long, leads along the base of outcrops of Tertiary age basalt on the edge of the Hedgpeth Hills. This is some of the youngest rock in our area — only about 15 million years old.

  I first visited this place on a beautiful, warm, autumn day, and it seemed that I had it all to myself. The sweet, dry smell of the desert surrounded me with comfort. I was walking along this peaceful trail, looking up at the cascade of dark rocks from above, when I was startled by an abrupt, booming voice from the chaparral around.

  “Hello, sir! May I be of help to you?”

  Totally surprised, I quickly turned around, and saw a man wearing a ranger’s uniform coming towards me from out of the bushes. He was Native American, or Indian (which is the designation he later told me he preferred), stocky, strong looking, with graying hair and chiseled features, and somehow he just “beamed”.

  He introduced himself, and I could see he was “official” by the badge on his uniform.

  In a very amiable manner, he immediately started dispensing information about the Rock Art Center, its history, and of course, the petroglyphs. But I was still trying to figure out why I had not seen him at first, how I had missed noticing him as I walked along that trail. After all, the chaparral there is not that thick or tall. And it seemed that he just “didn’t fit”; as if he had just materialized on the spot. I even had the thought that he was just posing as a ranger! I liked him at once.

  We stood in or near that same place for quite some time, talking about all sorts of things — his background, American Indians, history, artwork on stone that he produces on the side — it was fascinating. I never even made it to the end of the trail! I had to leave, as it was getting late, and I had another appointment. I apologized for having to end our enlightening conversation.

  Then one thing occurred to me strongly. I felt that I had finally met someone who really knew what the petroglyphs there, and elsewhere, were really about. I mean, what were those Indians really up to with all these drawings? I know, I’ve read all the ideas posited by present-day researchers about the markings being religious art, communication symbols, or maybe just plain graffiti.

  But why, in places like this? Why, in some places and not others? What was it about this rubbly, remote (in ancient times), harsh location that inspired people for thousands of years to spend a huge amount of energy creating all these drawings?

  Finally, here was someone who knew.

  So, before turning back along the trail, I explained to my guide my quandary. Those of you familiar with my other writings know where I am going with this: what is it about the rocks that energized the ancients here?

  “I am searching for that answer,” I pleaded, “and maybe you, being a knowledgeable Indian, and an artist, can tell me.”

  His answer was, to say the least, totally unexpected, and it came without hesitation: “Perhaps, sir, what you are really searching for is your own spirituality.”

*********

  If you want to do some “searching” along your own path, this is one place to begin. Go out there, and see what you feel in this special place. Take the Deer Valley Road Exit off I-17, and follow the signs, going west for several miles. The Center is closed on Mondays, and hours during the rest of the week vary with the season and day. You can get more information by calling 623-582-8007.

LandMark

Monday, November 14th, 2011

Camelback Mountain, in Phoenix, Arizona.

  Ask yourself which natural rock formation has come to symbolize Phoenix? Which one actually represents our city?

  Most people would say Camelback Mountain. Everyone here knows Camelback. Tourists from afar know of Camelback. And even those who have never been to Phoenix have somewhere heard that name, or read it.

  Rising almost out of the middle of the metropolitan area, it gives personality to our city. Like an actor who works best when able to “play off” of a certain other character, Phoenix has that statuesque mountain. More than just a prop, it is, many would say, the centerpiece of our stage in the world.

  If you are new to the Valley, or have just never noticed, when viewed from the south, the mountain’s profile does bear a resemblance to a reclining camel. You can see the head and neck on the west end, and the higher “hump” of the camel is the eastern part of the peak.

  Now since we are in the American Southwest, a camel would seem to be a figure unlikely envisioned in anything local. But there were camels in Arizona in the 1850’s—they were imported by the US Army, and used briefly for transport. That experiment didn’t work out very well, but since a camel’s association with the desert is almost a primeval thing, a sort of camel’s “essence” remains here.

  Few other cities in the world have such prominent, singular, natural monuments within easy reach. Rio de Janeiro, with its Sugarloaf, is one contender; or Capetown, South Africa, with its captivating Table Mountain. The Rock of Gibraltar certainly comes to mind, but it sits at the gate of the Mediterranean Sea, and is not really in a large city. And Ayers Rock, Australia? Well, it’s out in the middle of nowhere.

  Identity is a key factor in one’s psyche, and identification with landscape goes way back to when humans were just figuring out the world. For ancient Native Americans, the association with landscape was a given—for most of us in the modern-day world it is just a distant memory. But it is lodged deep in our minds somewhere, and without it we might as well live in underground bunkers, or windowless, modular structures without end.

  I feel sorry for space-station colonizers of the future, for they will never know the wonder of gazing up at a big, beautiful rock that can be seen for miles and miles, knowing that it is right in their own backyard, and that they can walk right on up it if they like.

  Although many don’t know it as such, Camelback Mountain is just one of the peaks in what are called the Phoenix Mountains. They cut our city roughly in half, and run from Moon Hill, on the northwest end (near I-17), to Camelback itself on the southeast end. North Mountain, Shaw Butte, Squaw Peak, and Mummy Mountain are some of the other well known prominences in the series.

  The whole group is what is known as a fault-block range. The Valley of the Sun owes most of its general appearance to a particular episode of geologic activity called the Basin and Range Disturbance, which ran from around 15 million years to about 8 million years ago.

  That span of time is a very recent part of Earth’s history, and so our setting is really one of geologic youth. The rocks which make up many of the mountains and features around us are very, very old, but they have just been recycled into the shapes we see now, that’s all.

  During that episode, the crust of our planet here stretched out and broke into pieces which run for miles and miles in more or less parallel orientations. With that activity, and because of gravity, some of those slabs started to settle down, alternating in a fashion with blocks left standing in between— the Phoenix Mountains are one such block. Millions of years of erosion then sculpted that high ground into the picturesque shapes we see now, one of which looks like a very tired camel.

*******

  The Valley’s “look” is very much due to “fault-block” mountains, like the Phoenix Mountains. The McDowell Mountains and the Sierra Estrella are also such ranges. But, there is another significant piece of the story of our setting, though, and that has to do with why our Valley floors appear to be so flat. In this case, I will also use Camelback Mountain to illustrate the point.

Camelback Mountain, from the summit of Squaw Peak, in Phoenix, AZ.

  The second picture here was taken from the near the summit of Squaw Peak, looking to the southeast. In it, Camelback Mountain has a shape very different from that in the first photo, where the “reclining camel” can be seen. In the forefront of this image is a ridge of the ancient metamorphic rocks of the Phoenix Mountains, on Squaw Peak.

  But behind it, you can see a small, level valley filled with the growth of civilization—a patchwork of cross streets lined with houses, buildings, landscaping, light poles and wires, and other signatures of humanity. On a mammoth scale, it looks here so much how like a colony of mold might appear in an old, forgotten bowl of Jell-O still open in your refrigerator, a dish with an uneaten piece of fruit left sticking out of the dessert’s firm surface. The mold relentlessly multiplies against the chunk’s base, ever struggling to breed its way up the sides of the lump.

  Similarly, Camelback rises out of that swale—its profile now a rugged, majestic pyramid— accenting the flatness all around it. The vast Sonoran Desert stretches out in back, for many, many miles.

  This view of Camelback Mountain alone, in my mind, makes the “workout” trek up Squaw Peak worth it. Just drive to the Phoenix Mountains Preserve, north of Lincoln Drive, park in the massive parking lot, and start up. For most, it will be slow going, but you will have lots of company. I have read that this hiking route is the busiest trail in North America, and it will indeed seem that way as you make your way up and down along with hundreds of other people, some young, some old; a few running, most walking, taking in the view.

  So why then, given that Earth’s crust is so broken up by the faults that delineated the Phoenix Mountains, is the surrounding landscape so flat? Shouldn’t we see a wilderness of canyons and gorges, and not the gentle valley floor that so readily harbors life and our comfortable, enviable world of greenery and strip malls?

  It’s that old, never ending story of “what is up, must come down”. Over the past ten or fifteen million years that our friend Camelback has been looming above the down-dropped blocks of rock once attached to its flanks, its slopes have also been eroding on a less exaggerated scale—a little bit here, a little bit there, day by day.

  All that sand, gravel, and clay has had to go somewhere, and where it ended up is simply down-slope in the deep basins surrounding Camelback Mountain, the Phoenix Mountains, and all the other ranges in our scenic part of the world.

  Over those millions of years, all of that eroded material—which geologists loosely call alluvium—has accumulated greatly in the Valley of the Sun and many other valleys of southern Arizona. Between all of the mountain ranges around here are deep, deep trenches. The actual bedrock surfaces of many of these basins are way below sea level, and many are thousands of feet below the surrounding landscape.

  That is why the land, out of which rises Camelback Mountain and the other peaks of the Phoenix area, is so flat. It is like a calm ocean of sand and gravel, barely rippling against the ranges, not revealing what lies beneath. What we see above it are simply the very tips of the mountains, in the same way that icebergs only show a small part of their true mass above the water’s surface, belying the real nature of what is unseen.

  In the case of our Camelback, it looks in my picture like it is separated from the rest of the Phoenix Mountains by the flat area, but “below the deck”, it is not. Down there, and here not too far down, underneath those houses, roadways, and trees, is the bedrock that connects all of the Phoenix Range together. Off to its south, and to its north, the fill material is much, much deeper.

  Thankfully, there is lots and lots of that alluvial fill, and those filled-in basins are wide and voluminous, for they hold vast amounts of groundwater—enough to keep that “growth” of civilization going for decades to come.

*******

  There is yet one more part of Camelback’s story—one missed by even the many hundreds of hikers who ascend its slopes daily: that of its role as an ancient sacred spot, where for centuries humans came to connect with their surroundings, or perhaps disconnect from them.

The Grotto in Camelback Mountain.

  Tucked low into the northern side of the rugged and strangely-shaped rocks of its western end, is a large cavity—a shady, cool cave that looks like it might have been designed as a band shell—a prehistoric amphitheater which even way back then was recognized as prime real estate.

  From inside it, the view to the north expands to include the Phoenix Mountains and Squaw Peak. Yet, there is a sense of enclosure, security, and especially of harmony. It’s not just because you are mostly surrounded by solid rock, offering safe haven from any attacker that might want to sneak up on you. No, it’s the feel of the setting that you notice. It feels rejuvenating.

  Many people are under the impression that primitive peoples thought of caves like this one simply as shelter. I would argue the opposite. The Hohokam people who lived in our valley up until around 1450 CE (current era) didn’t need shelter. They already had well-developed pueblos all over the area, as well as vast farm fields, extensive trade routes, and an elaborate culture. Indeed, they had other uses for such special places—what some would call magical places.

  The Camelback Grotto is one such spot. While standing in it, with the rocky, orange-brown, half-dome shaped ceiling some forty or fifty feet overhead, I couldn’t help but notice a close ridge of similar reddish sandstone and conglomerate a hundred yards or so out in front of the opening.

  The more distant mountains are off to the left—the ridge itself interrupts that background range as a natural sculpture of rounded and cave-riddled rock that looks organic, like a growth blooming up from the flat valley floor just below. That arrangement of rock not only adds to the feeling of the place—it is integral to it.

  The Grotto in the rocks of Camelback Mountain was formed by weathering and erosion. Those relatively soft sedimentary layers on Camelback’s west end have all been shaped by the same processes that also formed the scenic redrock buttes in nearby Papago Park, and in fact, they are part of the same geological formation.

  (The first photograph above was taken from the Papago Park area, near McDowell Road, looking north towards Camelback Mountain. The red rocks and buttes of Papago Park also stick out of the Valley’s alluvial fill—only they are lower in elevation and therefore less imposing. When such smaller formations poke up through the surrounding alluvium, they are called inselbergs.)

  It is possible that some of the opening’s shape has been modified by humans, but if so, not in noticeable fashion. As elsewhere on the mountain, the conglomerate unit contains small to massive chunks of much older, angular granite—evidence that these rocks resulted from very violent forces some twentyfive or thirty million years ago. It is serendipitous that such chaotic stone has evolved into the serene site it is.

  Why above do I say “connect”? Because that means changing a state-of-mind. Why do I say “disconnect”? Same thing: that means changing state-of-mind. It’s the change of mind that counts. The alteration of state-of-mind creates a sense of just being there, being absorbed in the present.

  Ancient Indian peoples looked at the landscape as part of their being, not just as something to utilize economically. It was not outside of them—it was part of them. Landscape exerted force on their daily lives, and influenced them in ways most of us just do not get or understand. Some places had the ability to amplify or modify those forces and influences, and the Grotto is one of those sites.

  The Camelback Mountain Grotto has been known to Phoenicians since around the time our city was established. People then visiting the cavern found and noted artifacts such as decorated, short, cane reeds. There were also lumps of salt, shell beads, small bones, arrowheads, and skyblue turquoise.

  But the reeds were particularly intriguing. They appear to have been ceremonial or ritual objects containing plant material, and were embellished with inked-in figures or marks. Wrapped around the outside of many of them was cloth fabric, and they were often found in bundles of four. Incense? Cigarettes? Who knows? Besides being a spiritual setting, maybe the Grotto was a party place, too.

  More than just a landmark, Camelback Mountain has been a special place for at least a thousand years.

  We are fortunate that it still is.
 

Turquoise Traders

Friday, October 14th, 2011

Mt. Chalchihuitl, in New Mexico.

  The drive through New Mexico had been long and tedious, and though I was tired, I was also excited to reach my goal. Just a few more miles, I thought to myself, and I’ll be there. This was to be the first of several places I had wanted to visit that are now known to be intimately tied to the history of turquoise in the New World.

  I was expecting the place I had been seeking to just jump out at me. But no, it turned out that it wasn’t that noticeable. Had I not been looking for it, I would have just driven on by, like the thousands of cars and trucks a day that zoom north and south between Albuquerque and Santa Fe, oblivious to the little group of small hills just east of the Interstate — another of those redundantly named places in the Southwest — the Cerrillos Hills. (Cerrillos means “little hills”, in Spanish.)

  Probably not one person in a thousand moving along that asphalt ribbon could have told you that in those barren looking hills is the oldest continuously mined site in North America. Like so many other places in our modern world where remnants of past greatness lie within reach of our everyday lives and yet go easily unnoticed and unconsidered, the Cerrillos Hills and their rich mines once shaped empires.

  The Indians of the Southwest, the Aztecs of Mexico, and later the Spaniards, would all come to know of this place and the treasure it once offered – the mineral we call turquoise.

  The world of gemstones is not just science. It also incorporates economics, psychology, art, and history. Especially history, since without tradition, there would be no real value to what otherwise would be just pretty little rocks. They’d be pretty, sure. But to have value, you have to have agreed upon tradition.

  Sometimes, as with diamonds, that tradition has simply been manufactured. Through intense advertising, for example, De Beers has created a tradition associating engagement, marriage, love, and eternity with diamonds. That very profitable tradition didn’t really exist before the twentieth century. I was searching for something much older, something not created by a marketing department somewhere.

  Turquoise is probably the oldest gemstone known. Its use in ornamentation goes back at least 7000 years. In the Americas, its place in history is vague, but, oh so intriguing. For with the continued evolution of our understanding of the extraordinary civilizations of North America, the history of turquoise is integral.

  That these hills are so unobtrusive serves as a kind of metaphor for the history of turquoise itself in the New World. When people in the Southwest think of turquoise jewelry, what undoubtedly comes to mind are large, clunky, elaborate pieces in which a multitude of blue stones are set into hand-worked silver necklaces, belts, and bracelets. The tourist shops and galleries of Scottsdale, Santa Fe, and Taos are loaded with them — some nice; lots of them junk.

  Most don’t realize that this style of turquoise jewelry is really a creation of the last one hundred and fifty years or so. Capitalizing on metal working skills learned from Spanish and Mexican artisans, Navajo, Zuni, and Hopi craftsmen started incorporating turquoise (from all over the Southwest, and now even Asia and labs in France where it is man-made) into silver jewelry. Railroads opened up the West in the late 1800’s, and the silversmiths’ creations found a ready market in the blossoming tourism business.

  Turquoise has one of those complicated chemical formulas that I was glad I didn’t have to memorize in college — a lengthy notation for hydrated, copper aluminum phosphate. We think of it as a blue stone, but green turquoise does occur also. Its composition is not nearly as interesting as its history, though, which goes way back beyond that of the 19th century Indians. Way, way back.

  By the way, our name for this gem, turquoise, is derived from a French phrase meaning “Turkish stone” — probably a reference to the fact that it was first imported into Europe by way of Turkey — its source in that case being mines in Persia, now Iran. Ancient Native Americans had their own name for certain highly sought-after green and bluish-green stones, turquoise among them. It is thought that also included with these gems were those we now call jade, and even poor quality emerald (remember, no one knew the difference between some mineral species until later science understood that they were different and had developed ways to tell them apart).

  For the most part, the earliest Americans apparently did not distinguish between blue and green hues. Both colors signified the same things: coolness, water, fertility. Within the Aztec pantheon of gods and goddesses, which of course evolved out of more ancient Indian beliefs, Chalchiuhtlicue was the deity of rivers and lakes, springs, and the sea. Her name translates as “She of the Jade Skirt”. Blue-green stones became known as Chalchihuitl, and from the association with water and life, they became symbolic, valuable, and objects of power within the shaman’s realm.

  Sources of the cyan-colored gems were varied, but through time one source became preeminent over all. We know it now as Mt. Chalchihuitl, somewhat centrally located in the Cerrillos Hills, and it is there that extensive prehistoric workings are found.

  For over a thousand years, turquoise mined there was carried vast distances by traders ranging over what became the Aztec empire and the outlying homelands of the Anasazi and the Hohokam. It became a basis for trade throughout the evolving cultures of the New World. Before the Spanish conquest, trade in Chalchihuitl would unite those native cultures in ways we are only beginning to understand.

  The Spaniards later laughed at the Indians’ love of the stone, for they were after what they considered to be treasures of much greater value: gold and silver. For those metals, the sacred mountain was a disappointment.

*********

 
Ruins at Chaco Canyon, New Mexico.

  Not more than several days walk from New Mexico’s Mt. Chalchihuitl lies an obscure canyon carved into brown, marine sands from the Cretaceous period. Wandering through the warm, tropical woods of those ancient times would have been the most famous of “terrible lizards”. Tyrannosaurus Rex and Triceratops fought bloody battles to the death there, while above nearby beaches soared evil-looking, winged reptiles — their narrow eyes fixated on the surf below, lest some tasty morsel go unnoticed. None of those creatures would recognize the area now.

  As you approach the canyon, its presence is not apparent. The view is one of flat table-lands — a desert of brush and scrub where struggling cattle simply maintain life from one day to the next. Only in the last few moments do you drop down and arrive among towering sandstone cliffs, and only in those last minutes does the feeling of the place supersede what the map portrays in such a dry manner.

  As I drew near the day’s objective, it took me by surprise, and it was another of those moments in life when I “got it”. This place is known now as Chaco Canyon. I literally couldn’t believe my eyes. I had seen pictures of it before, but they obviously hadn’t done it justice (just like my photo accompanying this article will not).

  I had read of its amazing ruins, and the dominance of its role in the Anasazi world of the time. And I couldn’t believe that I had waited so many years to come see it. It had just rained. A late afternoon thunderstorm had rolled through — thunder, lightning, and all — dropping the temperature by at least twenty degrees, and the desert smelled lush, lush. That only added sensuality to the scene, and as the low sun came out, and as the temperature rose again, I stood in awe of the setting spread out in front of me.

  What had possessed the old occupants of the enormous, walled, stone structures now lying there in ruin to build on that spot we will never know for sure. But it is one of those places where I am convinced that the power of the setting itself played a key role. We will also never understand what the residents of those massive buildings intended by living there, or what they called the place.

  But one thing we do know now is that the people of Chaco Canyon dominated the turquoise trade of their time. In fact, they may have been instrumental in developing it, and we also know now that the extent of their turquoise trade reached far into Aztec Mexico, and even to the heartland of the Hohokam civilization in what is now south-central Arizona.

  Present-day research shows us that the Chacoan Anasazi exploited the turquoise deposits at Mt. Chalchihuitl to a very great degree, and by way of a process called neutron activation analysis, we know that the sky-blue and cool green gemstones from the Cerrillos Hills made their way all over the American Southwest.

  Evidence uncovered during excavations at Chaco reveals that turquoise was likely traded for exotic birds from Central America, copper bells, and other treasures. Beginning at around 900 CE (Current Era), turquoise usage among the cultures of the region mushroomed, and this corresponds nicely with the rise and dominance of Chacoan culture. A vast system of engineered roadways radiates outward from Chaco Canyon, and it appears that it became the hub of a widespread turquoise trading network — its political influence even possibly based on the precious mineral.

  In diggings so far, over 200,000 pieces of turquoise have been recovered from the ruins of the “Great Houses” of Chaco Canyon. The Chacoans’ monopoly was not to last forever, though, and by 1300 CE turquoise had become common throughout the Indian communities of the Southwest.

  Was it just that major sources other than Mt. Chalchihuitl had been discovered? Had the Chacoans lost their edge in the trade? Maybe their power in the region had “gone to their heads”, and they had become self-centered and aggressive.

  Whatever the case, something sinister had started to happen. All you have to do is look around the region, even around the Valley of the Sun in south-central Arizona, and take note of where ancient settlements were being constructed — on steep, stark hilltops, on boulder-strewn and cacti-covered ridges, in places where no one in their right mind would build for the view alone.

  If you ever visit such now-crumbling ruins, one descriptive word will instantly pop into your mind: defensive. Were ripples of disintegration throughout Chaco culture being felt far and wide?

  Around 1300 CE the Great Houses of Chaco Canyon were abandoned. The turquoise mines of the Cerrillos Hills were quiet. And the deities of the blue gems of Mt. Chalchihuitl would have to wait for other servants.

*********

 
  With the demise of the Chacoan Anasazi seems to have come a general unraveling of cultures all over the northern highlands of the Southwest. Those traders of old had lost their political and social control of the region, as well as domination of the turquoise trade. The mines at Mt. Chalchihuitl would never again flood Mesoamerica with the blue-green gem of life.

  The high plateaus and mountains of New Mexico are not the end of the story, though, and I made my way towards home.

  In the 14th century, in the sprawling desert valleys of what is now south-central Arizona another civilization was just coming into its own. We now call these ancient people the Hohokam, which is a modern day Piman (Akimel O’odham) word meaning something like “those who have gone” or “all used up”. (Everyone who lives in the Phoenix area should at least be marginally familiar with their legacy. The city’s name owes its existence to early American settlers who realized the extent of the vanished society, and chose to rebuild on its ruins. Like the mythical Phoenix bird did after death, civilization there resurrected itself.)

  There is a lot that remains unknown about the Hohokam. However, many archaeologists do agree that they had more in common with the advanced civilizations of central Mexico (Toltec and Aztec) than any other Indian culture located in the geographic confines of what is the present-day United States. And the Valley of the Sun had likewise been home to one of the greatest centers of prehistoric civilization in North America, in terms of population.

  By some estimates there were fifty or sixty thousand people living in the area where Phoenix, Tempe, and Chandler now sit. They had devised and built a canal system which utilized around one thousand miles of canals to irrigate a body of land encompassing approximately a hundred thousand acres. That is about forty percent of what Arizona’s modern day Salt River Project now irrigates.

  From around 1300 CE, until their collapse at around 1450 CE, there is no question that the Hohokam dominated the Southwest — in cultural influence, food production, and trade. By some accounts, Hohokam-based traders may have ranged as far as Illinois, the California coast, the Yucatan Peninsula, and the Aztec capital of Tenochtitlan, now Mexico City.

  Agricultural goods, textiles, seashell jewelry, and turquoise would have been among their wares. Turquoise jewelry and carvings, once under the control of the Chacoans, had by this time become widespread throughout the Southwest. New mineral deposits of the gemstone had been found, too. Evidence now shows that turquoise was also imported into the Hohokam heartland from the Chalchihuites area, in Zacatecas State, Mexico (not to be confused with Mt. Chalchihuitl, in New Mexico). Other Hohokam turquoise artifacts have been determined to have originated from mines in what is now southern California, not far from Barstow.

  For decades, archaeologists have pondered the relative lack of turquoise objects among Hohokam ruins, and wondered why no evidence has been found of turquoise production facilities, or mining activity. Given the ancients’ propensity for trading, the sky-colored gem should be more ubiquitous in archaeological collections. What was lacking was the so-called “smoking gun” of Hohokam turquoise trade.

  Within the last decade, a site has been found in southern Arizona that just might be that “smoking gun”. On a remote hilltop, near modern day Tucson, sits the ruins of a place known in present-day Indian language as Na’Naksha’lKihhim — the “Village of the Scorpions”. Here are ruins of above-ground houses, a plaza, and a platform-type mound.

  Here, too, has been found evidence of turquoise processing and finishing, and now-spent mines. Although this particular site seems to have been abandoned while Chaco Canyon still dominated the turquoise trade to the northeast, it shows a clear connection to lands further south and is proof of the Hohokam presence in the turquoise trade. If all is as it appears here, the fusion of the civilizations of central Mexico with the Hohokam comes alive through turquoise.

  It was near sunset, and I stood there next to my idling car in the flat wastes, momentarily stopped on the shoulder of yet another roaring modern-day artery of trade. Wheeled vehicles whizzed straight from one horizon to the other. With every one that passed, a blast and thud of wind shook me and pushed me off towards the chaparral.

  Diesel fumes and automotive exhaust overpowered the nearby sweet smell of warm creosote — fading, then returning after each pulse of traffic. I could see purplish ridges and volcanic rock spires in the distance to the west, the landscape of the Village of the Scorpions, and momentarily, I daydreamed about life in the way-station on a trade route now vanished.

  I’ve noted above that what most people think of, when turquoise jewelry is mentioned, are the big, somewhat geometrical, multi-stoned silver ornamentations of the Navajos and Zunis, and that this style is only a recent invention.

Tesserae-style turquoise and shell jewelry.

  The real styles of the native, older occupants of the Southwest include beads, pendants, carved animal and bird motifs, and pieces composed of turquoise and shell tesserae. Tesserae are like little tiles, and were glued with pine resin to shells or wood pieces. This mosaic type is present in Aztec art as well.

  Pictured here is an ancient piece of turquoise jewelry, in the tesserae-style. This piece is a pendant with a small, reddish, center tile of shell, and measures about 9 centimeters (about 3.5 inches) across. While the pictured pendant is not Hohokam in origin (it is from the White River area in eastern Arizona), it is the closest thing I could find to photograph to show the style. It does date from approximately 1200 to 1400 CE.

  Trade routes shift, civilizations come and go, the world becomes ever more complicated and fast. But concepts of life, fertility, and coolness (especially in Arizona) linger — they remain, as does the stone that has come to symbolize them.

  True tradition never dies. It just changes hands, that’s all.
 

On Cloud 9

Sunday, July 3rd, 2011

Ancient petroglyphs on a basalt boulder in Phoenix, Arizona.

  The first time I walked up the trail on Shaw Butte, I didn’t even notice them.

  It took another trip, and a little exploring, and then I found what I had been looking for: a set of ancient ruins, and some people think, a prehistoric solar observatory. Actually, there is a sign there, posted by the City of Phoenix, asking visitors to respect these antiquities. Just behind a bush, it’s not easily noticeable from the trail, almost as if it had been planned that way. Like, “now that you’ve found this secret spot, please don’t damage it!”

  Just having read my opening lines here, you might already think you know where I am going with this article—another description of some of the Hohokam ruins for which the Phoenix area is famous.

  There is more than that, however, to this saga. These ruins are just part of a bigger picture that I want to present to you. Geology is not just something we study. Geology is something we are. By that, I mean that humans are inextricably connected to planet Earth and are part of its organic evolution.

  Those who think that nature is here for us to use, that it is at our disposal, have it all wrong. We are part of it. We are all one thing.

  For those of you not familiar with which of the peaks around Phoenix is Shaw Butte, you do know it. When traveling down I-17 from the north, it is the mountain on your left as you drive into the Valley of the Sun, just before you get to what we call Central Phoenix. The butte has a grove of tall metallic towers on its summit, and sort of a looming shape that to me has always suggested, “Welcome to Phoenix.” If you drive north on Fifteenth Avenue from, let’s say, Northern Avenue, you will run right into it.

  If you go around to the north side of the mountain, which some would call the “back” side, and look up, you will see a lot of black, rubbly-looking rock. Much of the north side of Shaw Butte is covered with this rock, known as basalt, or here, officially, the “Moon Hill Basalt”. It flowed up and out of volcanic vents around 20 to 15 million years ago. That sounds like a long time back, but actually these are some of the youngest rocks around the Phoenix area. You can see other areas of basalt around the Valley, too, and along the freeway to Flagstaff.

  When you look up at the Moon, the dark areas you see that form the “Man in the Moon” are basalt. Maybe that’s where the name of nearby “Moon Hill” came from.

  Those of you that have studied geology — even just the basics — know the three types of rocks: Igneous, Sedimentary, and Metamorphic. The above-mentioned basalt is an igneous rock, once molten.

  “New thinking” scientists now name a fourth rock-type —”Anthropic” rocks — rocks made, modified, or moved by humans. This new classificatory scheme now takes into account what should have been obvious all along.

  Think about how much of the Earth is covered with asphalt, concrete, bricks, shaped stones, and stones transported long distances (like maybe the counter tops in your kitchen). Even little gemstones are rocks which have been cut and modified by humans.

  We are transforming the surface of our planet in ways that other natural processes have never done, and in record speed! Like coral colonies in the sea which build colossal reefs, humans on their own scale add their signature to the world.

  I sat down in the musty dirt, in the middle of what is left of an 800 or 900 year old Hohokam room to ponder this concept, snacking from a bag of “Corn Nuts”, one of my favorite hiking foods. (Not that I’m really into “going native”, but these are very similar to what the Hohokam actually ate back then — roasted corn. How appropriate.)

  It had rained a few days before, and the desert still had that pungent, “wet-bushes” smell to it. The brittlebush all around glowed yellow in the low sunlight. I was all alone, and it was quiet except for the very dull roar of the suburban city stretching off below — traffic noise, occasional dogs barking, a yelled voice here or there, telling the dogs to shut up. I could see far into the distance, miles of human construction laid out everywhere.

  Black boulders surrounded me. They had been piled up to form walls, and pathways, and some sort of arrangement to guide the learned as to when to plant crops, when to get ready for the colder days of the year, when to celebrate whatever. Spiral petroglyphs had been etched into some surfaces. We will never know the exact purposes of this structure.

  Anthropic rocks. Shapes amidst geology, caused and formed by humans.   Unfortunately, I didn’t have a lot of time to linger there. It was an afternoon hike, just a break from work, and I had much more to do that day. I picked up my pack and walked on, past the summit, through who-knows-what-kind-of-radiation blasting out from the gigantic antennas above me.

  Then I found some more ruins, and an even better view.

*********

  It was when I walked up into another set of crumbling walls, down through an old staircase, and out onto a weathered concrete floor that the concept of Anthropic rocks — rocks made, modified, or moved by humans — really sank in.

Downtown Phoenix, Arizona, from the ruins of Cloud Nine.

  The view of Phoenix was grand. I was standing on a semicircular deck, looking out onto a valley below, filled with roadways and houses, and tall buildings in the distance. It was like an immense green carpet laid out there, the look of a garden amongst the barren rocky peaks.

  I had come across the ridge from the Hohokam ruins I had found earlier, and discovered this!

  I tried for a moment to put myself into the mindset of some Hohokam hiker, out for a day’s stroll from the solar observatory I had just visited. You know, like one of those old “Twilight Zone” episodes, where some lonely traveler rounds a bend in a remote road, only to find himself in some future setting, filled with strange structures, the purposes of which are unknown.

  As such, I tried to let my mind just view the scene, without judging it. In the distance, long silvery objects with wings were lifting up, out, and away from near the middle of the sprawl, while others glided down into it.

  My “Hohokam mind” wondered what had happened to the valley I knew, with its low adobe buildings, vast green fields, and long sinuous canals, rippling with life-giving water. My memories recalled how small columns of smoke rose here and there from the flats — signs of cooking, and warmth. There was no roar.

  It had been replaced by this! So similar, yet, so different in its look. There were long straight streets, the patches of greenery laid out in neat square blocks, and I could still see a canal or two. The fields? They were mostly gone, and gleaming buildings of all kinds were everywhere. There were what seemed like thousands and thousands of metallic objects rolling along on the roadways. I could hear distant sounds from them like I had never heard before, like the buzz of insects, but stronger and lower in tone.

  I snapped back to reality. I had once heard of this site where I stood — it was called Cloud Nine. I was standing on the floor of a classy old restaurant which had been named “Cloud Nine”, and it must have been quite a place before it burned down in 1964. A narrow, difficult road had once brought its guests up to this point high on Shaw Butte, where they could gaze out over Phoenix in style.

  You can see this spot today from I-17, as you drive by the mountain. Standing between what are left of its walls, I tried to imagine being there in days gone by, with maybe Sinatra or Sarah Vaughn on the jukebox, the lights of the city just coming on. At one table sat two businessmen talking up a deal; at another, in a dimly lit corner, a couple plotting infidelity over a couple of drinks. I could almost hear the plates rattling, the clink of glasses, and the sizzle of grilling steaks. They smelled delicious.

  Now, all that is left are these decrepit walls and flooring. If it weren’t for the City of Phoenix Park System, these would be gone, too. But here they have been preserved, not out of choice I presume, but because they are too difficult (i.e., expensive) to get at and remove, the land not being open for commercial development. What a great set of ruins!

  I hope the City leaves them alone forever. They have as much character as the older Hohokam ones, with every bit as much right to stay on the mountain. You just need to look at them with new eyes, that’s all.

The now-deserted deck of Cloud Nine, in the Phoenix Mountains Preserve.

  Though not with the original artwork, of course, the remaining walls are intricately decorated — some actually completely covered — with all colors of spray-painted symbols, slogans, and initials left by those intent on leaving their mark in the world. In their own way, those would-be artists came here on pilgrimages, whether to celebrate some event in their lives, to make some statement, or just to take in the magnificent view. I thought again about the petroglyphs I had just seen, on the boulders, over on the other side of the mountain.

  And here is where it all “clicked” for me — the subject of Anthropic rocks, I mean. I have always been very wary of “development”. I have always looked at the continual encroachment of human structures onto the natural world as a negative thing. And many times it is, to be sure. But here I realized that it is also a natural thing — a part of nature.

  As I said above, we are part of geology. Humans are modifying the surface of the Earth in drastic ways, and in big fashion. Cities, dams, highway systems, and canals are just a few examples. We are changing the nature of planet Earth faster than any other force. Whether in the form of Hohokam observatories or Cloud Nine ruins; whether in the form of ancient Hohokam cities or our modern-day metropolis, we are geology.

  What the Hohokam called their “city” we will never know. It was a human-made work of geology, situated in the Salt River Valley — a patch of structure on Earth’s surface. We call its new incarnation (appropriately) Phoenix — it too, a work of geological change, much more massive. What further will grow here in the future we can only guess about, and I have a feeling our vision will be way off.

  It’s hard to imagine 80 years into the future, let alone another 800.

Time is on my Side

Wednesday, November 3rd, 2010

Ferruginous quartzite (dark rocks) in Phoenix Mountains, Phoenix, Arizona.

  When I was young, growing up on the brown, flat Cretaceous rocks of central Montana, I used to fantasize about dinosaurs. It’s what got me into geology in the beginning, I guess. I was taken by the idea that where they roamed was right there, in the same physical space I was in at the time. Just about eighty million years earlier is all. Maybe a Tyrannosaurus Rex had actually walked across the ground occupied by my bedroom!

  People tend to visualize scenes from the distant past as though they were necessarily somewhere else. In space, I mean. But there were alien landscapes right here, just not now. This idea is conveyed in H.G. Wells‘ classic novel “The Time Machine”, now recently made (actually remade) into a movie.

  The movie does horrible justice to the original story, but you get the idea by watching the Time Traveler in his machine, sitting in one spot, with the “hours-days-years” odometer rolling on in a blur. He starts the machine and his journey through time in his laboratory in London. At one point (in the book) he “lands” in a rhododendron garden looking over the River Thames, surrounded by alien structures; in another scene he is on a barren beach in the distant future, watching a dying red sun setting into a future ocean of dead, spent waters. All those scenes occur in the same place.

  Back to Phoenix and now, in which the landscape is far different from way back then, let’s say, in Precambrian time, for example. Take a drive on SR 51, the Piestewa Freeway, where it cuts through the Phoenix Mountains, just to the northwest of Squaw Peak, and you will see what I mean.

  If you are going north, look off to the west (left) just after you have passed the Northern Avenue Exit; if you are going south start looking west (right) about the time you get to the Exit ramp. If you like to walk, you can park in the Dreamy Draw area, and approach this area from one of the trails in the Phoenix Mountains Preserve, a city park.

  About half a mile away, up on the east slopes of those rugged rocky peaks you will see dark brown, almost black areas of broken up rocks and rubble. Some of this rock forms a pointed outcrop just at the south end of that set of hills, and is also visible elsewhere in the Park. There are a few houses (with great views of the Valley, to be sure) to the north of these rocks, near a saddle.

  What you are looking at are the remains of ancient, submarine hot springs — very ancient, and very submarine, from the bottom of an ancient ocean. These rocks have the wonderfully technical name of “ferruginous quartzites” and the hot springs that formed them erupted, seethed, and bubbled about 1700 million years ago, at the bottom of a vast sea whose only occupants were life forms so primitive that you would have needed a microscope to get their names. The hot springs were rich in iron, and those iron minerals give the rocks their current color.

  The Phoenix Mountains are made of a section of the earlier crust of Earth where the rocks were formed in an environment somewhat like that off the coast of present day Japan. If you were to walk from the freeway in Dreamy Draw over to Shaw Butte (about 4 miles), you would be going right down through rock section (now standing on end, basically), that shows the whole evolution of that environment. If you were going to strap yourself into Wells’ Time Machine, and dial up, say, April 10, 1,700,000,000 BC, you had better already be wearing your deep-diving equipment!

  Our planet’s crust is in constant motion. The shapes of the land masses we know today are as ephemeral as the shapes of clouds in the sky. The continents move about relentlessly, literally floating on top of more dense fluid rock below. Heat from deep within the Earth sets huge convection currents into motion, causing continental rocks above to glide about, sometimes crashing and fusing together, sometimes splitting into new shapes, all of it happening all of the time, just in too slow of a fashion for us to grasp easily.

  Our journey through time would take us to the edge of one of these land masses, where heat from the gargantuan convection cell below has broken through, boiling the waters, and creating a primordial soup in which early life prospers.